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Visual diagnosis of plant disease following a visually evident epidemic results in untimely and excessive application of pesticide. Conventional nondestructive testing methods are difficult for early recognition before the onset of symptoms. In this study, tomato mosaic disease and wheat leaf rust were taken as examples. Infrared thermal imaging technology was used to continuously detect the temperature information of the two crops during the incubation period following the introduction of inoculum. Diseases of tomato and wheat were induced by rubbing inoculation and spray inoculation, respectively. Maximum temperature difference (MTD) was calculated to characterize the continuous temperature change during the incubation period. The results showed that the MTD of tomato mosaic disease ranged from 0.2°C ~ 1.7°C, and that of wheat leaf rust 0.4°C ~ 2°C. As the disease progresses, the MTD of both plants showed an increasing trend while the average temperature decreased. The time to observe the symptoms earlier than the naked eye for tomato mosaic and wheat leaf rust is 5d and 7d respectively. Studies showed that it is feasible to realize the early determination of disease through the combination of infrared thermal imaging and MTD calculation. It provides the theoretical basis and method basis for the early and accurate application of spraying.

Interest in native species is growing across the tropics as reforestation of degraded lands becomes more widespread. In this study four tree species native to Panama – Cedrela odorata , Pachira quinata , Samanea saman , and Tabebuia rosea – were grown on rural farms at two dry tropical sites in Panama for up to five years. Survivorship and growth data at these “on-farm” trials are compared to data recorded from nearby experimental or “species selection” trial sites and evaluated in terms of soil fertility and management. Participant farmers were also asked about their interest in planting trees in general as well as their interest in 61 species grown in the species selection trial. Although, on-farm survivorship was variable and generally lower than that found on the species selection trial, one species ( S. saman ) experienced high and consistent survivorship. High survivorship combined with growth data from farms at both sites for this species suggests it would be a good candidate for extension projects working with rural farmers. Survivorship of other species appears more sensitive to farmer management and/or local site conditions. Generally lower growth on the Los Santos farms as compared to the species-selection trial is attributed to the lower soil fertility (plant available P) at the on-farm sites compared to the species selection trial. In contrast, only one species – P. quinata – had a growth variable found to be significantly lower between the on-farm and species selection trial sites in Rio Hato. C. odorata , P. quinata T. rosea can all be used in on-farm conditions with consideration to specific site and management conditions. By 2009, approximately 80% of the farmers planting trees still wished to participate in tree planting activities. All of the farmers no longer wishing to continue with the project expressed slow growth rates of trees as a principal reason. All but one of these farmers had growth rates for his/her trees markedly below those of the species selection trial nearby. Some farmers wishing to continue had very high mortality rates (>70% for all species), suggesting non-tangible benefits for participating in project activities. Other species that were not tested on-farm but grew well in the species-selection trials and were of interest to local farmers are discussed. As long as specific site and management conditions are carefully considered, data from species selection trials can be useful in informing tree planting projects with rural farmers; however, care should be taken to manage expectations.

Drought stress is the most important abiotic factor limiting upland rice yields. Identification of quantitative trait loci (QTL) conferring improved drought resistance may facilitate breeding progress. We previously mapped a QTL with a large effect on grain yield under severe drought stress (qtl12.1) in the Vandana/Way Rarem population. In the current paper, we present results from a series of experiments investigating the physiological mechanism(s) by which qtl12.1 affects grain yield under drought conditions. We performed detailed plant water status measurements on a subset of lines having similar crop growth duration but contrasting genotypes at qtl12.1 under field (24 genotypes) and greenhouse (14 genotypes) conditions. The Way Rarem-derived allele of qtl12.1 was confirmed to improve grain yield under drought mainly through a slight improvement (7%) in plant water uptake under water-limited conditions. Such an apparently small increase in water uptake associated with this allele could explain the large effect on yield observed under field conditions. Our results suggest that this improvement of plant water uptake is likely associated with improved root architecture.